It'd be better if you open the cfg and edit wheel slots by hand instead than using that crappy program.
These are the rows you need to edit:
FL wheel
type 10.000 sphere 0.315
spring 0.290 0.100 0.050
wheel -0.6559 -0.4163 -1.1804 0.000 0.000 0.000 1.000 1.000 1.000 0.000
FR wheel
type 10.000 sphere 0.315
spring 0.290 0.100 0.050
wheel 0.6559 -0.4163 -1.1804 0.000 0.000 0.000 1.000 1.000 1.000 0.000
RL wheel
type 10.000 sphere 0.315
spring 0.290 0.100 0.050
wheel -0.6559 -0.4163 1.1663 0.000 0.000 0.000 0.000 0.000 1.000 1.000
RR wheel
type 10.000 sphere 0.315
spring 0.290 0.100 0.050
wheel 0.6559 -0.4163 1.1663 0.000 0.000 0.000 0.000 0.000 1.000 1.000